a) Field of the Invention
The present invention relates to a forming machine for fabric slats, and more particular to a forming machine which enables a thermoplastic strip of fabric to be hot ironed with contact on an entire surface thereof, in a linear motion and in a whole procedure, for largely removing a deformation stress, as well as to be cold ironed and re-shaped, wherein temperature in the procedure can be exchanged gradually, such that structures of elements can be dislocated sequentially for stable deformation, thereby shaping the slat of a curved cross section.
b) Description of the Prior Art
For a blind curtain used for shading from light, especially a horizontal blind which is formed by joining a series of slats, the slats are required to have upright mechanical strengths to defy gravity that they can be constructed on the horizontal blind for use. The slats can be made by natural wood or bamboo, or can be even shaped by aluminum or a plasticized board material. The abovementioned materials are light impermeable or their refraction surfaces are optically cold and dull after refraction; therefore, a mood of gradation is unable to be manifested. Accordingly, there is provided with a blind set using draperies to shade from light. In addition to that a semi-transparent effect of this blind set can provide part of refraction light, sensuousness of textures is able to be discriminated as the textures of fabric are supported by outdoor background light; this is an ancient culture of the blind and is difficult to be replaced.
In earlier days, there were vendors who utilized a woven fabric which is dipped in a plasticized adhesive agent to form a slat for use after drying, in order to allow the horizontal slats to be partially light permeable, replace the materials to convert an economic benefit, as well as manifest the more enriched textures and coloration. After the woven fabric has been constructed on the blind set, the partial light permeability can be achieved and the textures of fabric are discriminated.
As the early technologies are not perfect, an improved technology is being actively developed for high production speed and serving as a basis of applicability. In 1990, a Taiwanese vendor has filed a patent application, No. 79107755, which claims a technology of formulating compositions of an impregnated substance (i.e., the plasticized adhesive material) of a fabric Venetian blind (i.e., the horizontal slats) and a vertical blind. In this patent, the fabric is first impregnated with the adhesive agent, allowing pores and surface of the fabric to fully adsorb the adhesive agent. Next, after an operation of tension adjustment, the fabric is heated up and compressed on a shaping machine to result in the fabric slat that is impregnated with the adhesive agent. This fabric can be used in the horizontal or vertical slat.
Through the abovementioned patent, it is known that by dipping the fabric in the plasticized adhesive agent and utilizing a structural force of solidification of the plasticized material, the fabric can be supported to be used for the horizontal slat. In addition, this patent has also disclosed a concept of hot-work shaping.
An explicit operation technology of the abovementioned hot-work shaping was disclosed in 1992 by a Taiwanese vendor who filed a patent application, No. 81202945, which is an apparatus for forming the fabric slat. As shown in FIG. 13, the apparatus includes a heating tank which is connected at an upstream end with molding tool for forming at a downstream end. A strip of fabric is fed into the heating tank by another set of guide rollers and an output end of the molding tool is provided with a set of rubber rollers to take up the fabric strip. From the drawings and texts, the heating tank is an empty tank unit having a chamber. Furthermore, in the summary of the invention, a top of the heating tank is sealed by a cover plate and the strip that enters is suspended in air or cut, allowing a surface of the fabric strip to be softened by heating. The heating process is only for softening and shape styling is not implemented until the fabric strip enters into the molding tool at the downstream end.
After the abovementioned patent has been issued, another amended technology was filed for application, as in the patent application, No. 81202945A01, which claims a closed heating box heated by electrothermal tubes. In this invention, the fabric in the heating box travels along an S-shaped path and therefore, the heating path is extended that the fabric can be softened uniformly only after heating for a long time. In addition, the heating process is like baking, where the fabric is heated up with spatial separation.
In 2006, a U.S. patent application, Ser. No. 11/459,529 was filed and was published in 2007 with No. US2007/0023962A1. This patent discloses a method and an apparatus for forming fabric slats. In the claims, the method is implemented by the apparatus which includes a first driven roller to pull a strip material, an elongated heat chamber through which the strip material can pass and be thermally softened, a cooling station downstream from the heat chamber, an elongated support of an arcuate transverse cross section extending through the heat chamber to support the strip material, and a second driven roller for pulling the strip material through the heat chamber and the cooling station.
The heating means as described by the abovementioned patent utilizes a heat chamber which is an elongated hollow tube as described in claim 3. In claim 4, the heat chamber is provided with a closure system at each end, with a slot through which the strip material can pass. In claim 5, a pre-heat section is provided at an upstream end of the heat chamber and in the summary of invention, that pre-heat section is known to preheat the chamber body not the fabric. In claim 7, a scraper having an arcuate opening is provided on the arcuate surface of the support. Accordingly, by the texts and drawings, it can be clearly known that the heating means utilizes a chamber and the so-called chamber is a space with a room. Therefore, the fabric is heated up by a thermal radiation wave; this is a heating method with spatial separation and is similar to the Taiwanese patent application No. 81202945. During thermal melting, thus, the fabric is not styled and the implementation of styling (curved cross section) is based upon that in a processing line of the cooling station, a mechanical force of scraping and compressing is exerted onto the softened strip material which travels through a gap between an upper surface of the support and the arcuate opening of the scraper. Besides, the scraper is a piece of plate and a void space between the two scrapers allows cold air to directly blow onto the upper surface of the strip material to dissipate the heat.
The abovementioned design provides a solution of continuous forming operation to quickly shape the fabric, which has been accomplished with the adhesion process, into the slat with the arcuate curve.
In the implementation of the two abovementioned prior arts, it can be clearly seen from the texts and drawings that the strip material is heated up with spatial separation by the heat wave, allowing the entered strip material to be softened, so as to prepare for the subsequent operation of shaping and styling. In other words, the shaping operation only relies on the elements provided by the subsequent cooling station and during the heating process, only the strip material itself is self deformed by softening, with the gravity acting as the external force for deformation.